[Haskell-cafe] catch the stdout when execute a shell cmd

[Donald Bruce Stewart]

oxware:
> I use "system" in System.Cmd to execute a shell cmd, then how can I
> catch its stdout?

Use System.Process,
    http://haskell.org/ghc/docs/latest/html/libraries/base/System-Process.html

And example, call the 'date' program:

 > (inh,outh,errh,pid) <- runInteractiveProcess "date" ["+%d:%m:%y"] Nothing Nothing
 > hClose inh
 > hGetContents outh
 "24:01:07\n"

Regards,
  Don

There's some wrappers to this floating around too, which should get into
base soon enough.. E.g. http://www.cse.unsw.edu.au/~dons/code/newpopen/